Ok, it would be nice to have the Grouping tag available, although as you say, this can also be solved using other tags. My two favorite programs that I use for mp3 (MusicBee and TagScanner) have the Grouping tag among the basic ones.
I have another request: On the All albums tab, sorting can be set. However, the menu is missing sort by Album-artist. Please add this option.
And also about the options for displaying extra images in the application. If you select an album on the Albums tab, there is an option Change local thumbnail on the cover image. This will take you to the file browser (select from file picker), where jpg files are already visible and here it is possible to view images using, for example, the system Photos application, without changing the local thumbnail. This works well. The only problem that would be good to solve is how to get to the relevant folder directly. I see two options here. Either the option to change the thumbnail would lead directly to the necessary folder or, which would be more elegant, the path to the file being played is listed in the album detail on the player tab. This path could be clickable and this would open the directory containing the file being played. Or maybe there is another way, but I can’t think of anything right now.